Agricultural dehydrating and cooling system

ABSTRACT

A furnace for providing dehydrating gases has its flue connected in series with a multiple-pass dehydrating drum compartment by longitudinal radial partitions to promote efficient intimate exposure of material to dehydrated gas by subdividing both the gas and the material into narrow streams while still providing the tumbling which results from drum rotation. The light output of the drum is delivered through a settling chamber into a cyclone separator which has its gas discharge port connected to a blower that subjects the chamber and drum and furnace to vacuum. The light solids are then recombined with heavy solids before discharge. Discharge of solids without access of air is controlled by a rotary valve which has generally radial vanes protected from breakage by provision of angularly yieldable end portions.

United States Patent 7/1935 Fasting 4/1937 Arnold 11/1952 Arnold.........................

[ pp 807,802 FOREIGN PATENTS 5/1935 Netherlands.................

Primary Examiner- Frederick L. Matteson Assistant ExaminerTheophil W. Streule [22] Filed Mar. 17, 1969 [45] Patented Sept. 7, 1971 [73] Assignee said Gerald D. Arnold, by said John B.

Arnold Attorney-'Wheeler, Wheeler, House & Clemency [54] AGRICULTURAL DEHYDRATING AND COOLING ABSTRACT: A furnace for providing dehydrating gases has its SYSTEM flue connected in series with a multiple-pass dehydrating urn compartment by longitudinal radial partitions to 1 Claim, 8 Drawing Figs.

promote efficient intimate exposure of material to dehydrated gas by subdividing both the gas and the material into narrow streams while still providing the tumbling which results from drum rotation. The light output of the drum is delivered through a settling chamber into a cyclone separator which has its gas discharge port connected to a blower that subjects the chamber and drum and furnace to vacuum. The light solids are then recombined with heavy solids before discharge. Discharge of solids without access of air is controlled by a ro- 34/136, 222/368, 55/432 [51] Int. F26b 17/00 [50] Field of 34/109, 128,136,135, 79, 57, 57 D; 55/267, 430, 459; 222/368 [56] References Cited UNITED STATES PATENTS 7/1955 Cassells........................

34/135 tary valve which has generally radial vanes protected from 34/136 X breakage by provision of angularly yieldable end portions.

10/1962 Downing. .....r..............

PATENTEB SEP um sum 1 (If 3 PATENTED SEP 7 l97l SHEET 2 OF 3 PATENTEH SEP 7 WI SHEET 3 BF 3 INVENTOQS 65241.0 0. REA/00D HN 5.1Q2n/OLD ATTORNQNS AGRICULTURAL DEI-IYDRATING AND COOLING SYSTEM BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION longitudinal partitions in the drum and about the end. These assure that substantially all portions of the dehydrating gas will be tumbled while fully exposed to the produce or grain or other solids to be dried.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a general view in side elevation of a dehydrating system embodying the invention.

FIG. 2 is an enlarged detail view in transverse section through the valve which controls the discharge of solids from the separator.

FIG. 3 is a fragmentary view in axial section through the drum on a considerably enlarged scale.

FIG. 4 is a further enlarged detail view taken in section on the line 4-4 ofFIG. 3.

FIG. 5 is a view taken in section on the line 5-5 of FIG. 3.

FIG. 6 is a detail view taken in section on the line 66 of FIG. 3.

FIG. 7 is a fragmentary detail view showing a modified partition and baffle arrangement.

FIG. 8 is a fragmentary detail view partially in section and not only the heavier dehydrated material but also any foreign matter such as stones or iron. All such material will be received by conveyor 50, recombined with light material from the separator 48 and discharged downwardly by gravity partially in perspective showing a modified flight arrangement.

DETAILED DESCRIPTION The nonrotatable furnace drum 14 has a generally tangential fuel and air inlet at 16. I

A flue pipe 20 leads toward the dehydrator drum head 22 at the inlet end 24 of the rotatable mounted drum 26. A motor 25 rotates the drum on supporting rollers 190. A rate changer 27 preferably intervenes in the drive from the motor to the drum to enable the operator to control the speed of drum rotation. The material to be dehydrated is elevated by conveyor 28 and delivered into a hopper 30 which communicates through a rotary valve 32 with a throat 34 through which the dehydrating gas from furnace l4 enters drum 26. The entire system is preferably maintained under partial vacuum by an exhaust fan 54.

A spray nozzle 36 has a water supply connection 38 which delivers water directly onto the produce 40 on conveyor 28. The amount of water is controlled with discharged gas temperature as explained in Arnold US Pat. No. 3,360,868 to prevent scorching of the material'in the drum while assuring complete dehydration thereof. In addition to preventing scorching, the moisture and heat together are effective in degradating pesticides and antibiotics on the produce, whereby to protect animals and milk from contamination.

Details of the drum construction will be explained later.

Dehydrated material issues from the outlet end 42 into settling chamber 43 from which the pipe 44 carries the dehydrating gas and the lighter entrained dehydrated solids upwardly to the tangential inlet 46 of a centrifugal separator 48. In its upward movement, the dehydrating gas will tend to drop out through the rotary discharge valve 51 onto discharge conveyor 50.

The gases are withdrawn from the cyclone separator 48 by means of said exhaust fan or blower 54 operated from'motor 56 through a speed controlling rate changer 58. The gases discharge into the atmosphere at 60. The solids pass through a rotary valve 51 onto conveyor 50 (as previously described). This conveyor is sealed from the atmosphere by housing 75 from which solids are delivered through rotary valve 76. Discharge is effected on conveyor 78.

THE DRUM CONSTRUCTION The drum 26 as shown is a rotatable triple-pass drum. There is an inner shell 80, an intermediate sleeve 92, and an outer shell 126. The clearance between the inner shell and the throat 34 is sealed against the admission of atmospheric air by a floating sealing ring 112 bearing on throat 34 and guided by suspension from brackets 114 as best shown in FIG. 3. The seal ring 112 is held by partial vacuum against the end of inner shell 80. Y

The dehydrating gas and the entrained material 40 to be dehydrated enter through the throat 34 into the inner tubular shell 80 which is divided by short radial partitions 82 into arcuate segmental passages 84. These passages are further divided by flights 86 riveted or welded to the inner shell 80. During drum rotation the partitions 82 and the flights 86 lift the materials to be dehydrated and drop it across the path of dehydrating gases traversing the narrow segmental passage 84 longitudinally of the drum. Some of the material drops repeatedly across the center portion of the drum where it is exposed to the gases passing through the center. However, it will be noted that practically none of the dehydrating gases will escape exposure of the material thereto. This exposure of the gases and the material to each other continues in successive drum traverses.

Once the material enters one of the passages 84 it is segregated from other material all the way through the intermediate and outer drums.

The central tube or shell 80 has its end 88 sleeved in a ring 188 supported by the gussets 118, one of which is shown in FIG. 4. Similarly the intermediate drum or shell 92 is supported by gussets 127 and ring 192 from the outer shell 126 (FIGS. 3 and 4). The dehydrating gas and the material sweep around the end 88 into the passages 90 between the inner shell 80 and the intermediate shell 92 (FIGS. 3 and 5). Generally radial partitions 94 delineate arcuately segmental passages 90 which extend longitudinally of the drum between sleeve 92 and the inner shell 80. Into each of the passages 90 extend flights 96 from the inner shell 80, flights 98 from the partitions 94 and flights 100 from the intermediate sleeve 92. The flights preferably are backwardly pitched as shown in FIG. 8 and have flanges 87 riveted or welded at 89 to the respective shell or sleeve.

Radial partitions 94 have outer margins 104 and inner margins 106, respectively slidable in channels 108 provided by the fittings 110 attached to respective shells. The ends of these partitions line up with the gusset plates 118 which, in turn, are in the same plane as the partitions or flanges 82 in the interior of the inner shell 80. They also line up with partitions 119 which subdivide the inner section 23 of the end 22 of the dehydrator. Bolts 120 connect the inner section 23 with the outer section 21 of the end member 22. When these bolts are removed, the central cylinder 80 with the partitions 82 on the interior thereof and the partitions 94 on the exterior thereof may be axially removed unitarily from the rest of the dehydrator. However, the bolts 124 extending through gusset plates 128 in a radial direction are provided with nuts 131 in the apertures 130 of gusset plate 118 to prevent withdrawal.

and disposed radially between the intermediate sleeve 92 and the outer shell 126 provide segmental passages 132 into which flights project in the same manner as between the inner shell 80 and the intermediate sleeve 92. Material which has traversed the intermediate passages 90 is guided by the curved end to enter the external passages 132, these being traversed from left to right as viewed in FIG. 3.

Aligned with the partitions 134 between passages 132 are the gusset plates 128 referred to above. These are aligned, in

turn, with partitions 140 between the conical end wall 138 and the conical interior baffle 136 (FIG. 3). This baffle guides the material and dehydrating gas to throat 139 which is loosely telescoped over the delivery pipe 44 above mentioned. Encircling this pipe is a sealing ring 112 identical with the sealing ring at the inlet. Ring 112 is seated against flange 135 on the end of pipe 44. The ring 112 is held to the flange 135 by partial vacuum produced within the system by the suction of the blower 54. The ring floats under guidance of the chains 149 which may be connected, for example, with the brackets 114 on throat 139.

In practice, the solids pass downwardly through the cone 150 because of the fact that the discharge pipe 172 is normally closed against air admission, being equipped with a rotary valve 51. As will be noted in FIG. 2, the liner for the valve housing 51 is eccentric with the housing where it has a lip portion at the point where it connects to a throat or discharge pipe 172. Elsewhere the valve vanes 182 are in close proximity to the liner but they have increased clearance from the liner at the lip where the material enters the housing so that such material will not be sheared by the vanes at thispoint. This is of particular importance when the material consists of grain such as corn. But for the described construction, the corn might be cracked by the vanes.

THE ROTARY VALVE A power driven shaft 176 carries fixed vanes 178 which are not radial but rearwardly inclined and which extend only part way outwardly from the shaft. At corresponding points, each of these vanes'is provided with a hinge 180 for a yieldable vane extension 182 which is normally biased into alignment with the vane 178 but is yieldable backward. The direction of rotation is indicated by arrow 184. The spring 186 holds each of these vane extensions in its retracted position as shown but each is yieldable in a clockwise direction as viewed in FIG. 2, against the bias of spring 186 if the blade is impacted by iron or other hard material which may reach this point in the apparatus, the object being to avoid damaging the valve. As

shown in FIG. 2 one of the vane extensions is shown in dotted lines in a position to which it has yielded against the bias of its spring 186.

In accordance with routine practice, the outer shell 126 carries peripheral riding rings 188 which are supported on rollers 190 to facilitate rotation of the drum 26. The gussets 128 at the outlet end of the drum carry rings 192 which support the intermediate sleeve 92, similar support being provided at the inlet end of the drum by rings 194 supported by gussets 196 from the outer shell 126. The intermediate sleeve 92 is axially slidable telescopically into and from the ring 192, being held in position during normal use by the bolts 124 already described. The mounting of the inner shell which supports its weight from the riding rings 188 is similar, the gusset 118 between the inner shell and the intermediate sleeve providing support for the rings 188 as already described. The ring 200 into which the inlet end of the inner shell 80 is sleeved is carried by the head 22 which supports it directly from the riding ring 188 which is closest to the inlet of the dehydrating drum.

The parts are readily assembly by telescopically sleeving them together as already described. It is equally easy to disassemble them simply by removing the inner shell 80 from the internally projecting partitions 28 and disconnecting the bolts 124 so that the intermediate sleeve can be withdrawn through the previously disassembled section 23 of the head 22 at the inlet end of the drum.

In practice, the dehydrating gases include products of combustion and additional air. They are very hot when they issue from the furnace and traverse the throat 34 in which the material 28 to be dehydrated is introduced through the valve 32 with its surfaces thoroughly wet by the water directed upon them through the spray nozzle 36. This water is immediately evaporated and turned into steam at temperatures above 212, at which temperatures the moisture contained in the material 28 is also evaporated.

It is a basic feature of the present invention to subdivide the interior of the drum into longitudinally extending passages which are quite narrow circumferentially so that the material to be dehydrated is tumbled during drum rotation while confined quite closely in the path of the gases traversing the particular passage in which the material is being tumbled. It is to be noted that in the preferred structure shown each passage is continuous and distinct from all other passages about the curved heads from one cylinder to the next. This maintains a much more intimate contact between the dehydrating gases and the material upon which the gases are acting and the result is to achieve more quickly the very effective dehydration of such material. Various baffles which project from the tubular shells and sleeve and the generally radial longitudinal partitions serve to distribute the finely divided material throughout the cross section of the drum in the course of drum rotation.

The rate of evaporation is fast enough so that notwithstanding the initial high temperature of the gases, the material is kept cool by evaporation and never rises high enough to become oxidized. Accordingly, the dehydrated material discharged will have substantially natural color notwithstanding that it is sufficiently dry to keep indefinitely.

We claim:

1. A dehydrator comprising a rotatable drum having an inlet at one end and an outlet at the other, a suction fan for effecting flow of dehydrating gases and material through the drum, a cyclone separator connected in series between the drum and the fan for segregating dehydrated material from the gases which have acted thereon, said separator including a tapered separating chamber and a discharge port for solids opening from the smaller end thereof, a normally closed rotary discharge valve controlling flow through said discharge port, said valve comprising a rotatably mounted shaft and outwardly projecting vanes mounted thereon, each such vane having a vane extension in hinged connection therewith, means for biasing said extension to project outwardly from the vane to which it is hinged, and a valve chamber substantially closed by the several extensions when they are in the normal position to which they are biased, each such extension being yieldable upon its hinged connection to pass objects foreign to the material being dehydrated. 

1. A dehydrator comprising a rotatable drum having an inlet at one end and an outlet at the other, a suction fan for effecting flow of dehydrating gases and material through the drum, a cyclone separator connected in series between the drum and the fan for segregating dehydrated material from the gases which have acted thereon, said separator including a tapered separating chamber And a discharge port for solids opening from the smaller end thereof, a normally closed rotary discharge valve controlling flow through said discharge port, said valve comprising a rotatably mounted shaft and outwardly projecting vanes mounted thereon, each such vane having a vane extension in hinged connection therewith, means for biasing said extension to project outwardly from the vane to which it is hinged, and a valve chamber substantially closed by the several extensions when they are in the normal position to which they are biased, each such extension being yieldable upon its hinged connection to pass objects foreign to the material being dehydrated. 